Energy storage or phase change materials (PCMs) are able to store and release large amounts of energy at temperatures where a physical phase change occurs (e.g., solid-liquid, liquid-solid transitions). Phase change materials have a high heat of fusion which means they are particularly useful to control heat energy transfer. The primary applications in which phase change materials can be useful are when heating or cooling infrastructures are not available such as during camping or travelling, military operations, medical applications, and other situations that require convenient access to temperature-controlled products.
Phase change materials offer tremendous potential to fulfill the growing energy needs for cooling and heating applications across various industries, including construction, commercial refrigeration, textiles, and smart food packaging. Building and construction currently forms the largest application market due to the globally increasing demand for cooling buildings, which in turn has arisen due to the shift from heavy thermal mass design to lightweight architecture. The use of the passive phase change material technology is expected to boost the global efforts to conserve energy in the wake of fast depleting fossil fuels. However, effective integration of phase change materials in end-products remains a challenging task.
Of the known phase change materials, polymeric-based materials represent the most widely used category due to their low density, and ease of processing. Most of the commercially available phase change materials are simple paraffinic-based composite materials encapsulated in a containment vessel in the desired form factor. Commercial paraffin wax alone is often not practical because of its relative inefficiency and high transition temperature. Paraffinic-based composite phase change materials typically have low efficiency and are expensive, especially if pure or virgin hydrocarbons are used. Recently, DuPont released an advanced paraffinic-based copolymer product from virgin hydrocarbons in sheet form intended for use in commercial and domestic floor heating.
There remains unmet needs for improved phase change materials that further tailor transition temperatures and maximize stored energy, eliminate the need for a separate containment vessel, are made from waste streams, and that are food safe or GRAS (Generally Recognized As Safe) approved.